breadpad: add --screenshot CLI mode for automated capture

Same reasoning as breadbar/breadbox/breadclip/breadsearch, but plumbed
through breadpad's own hand-rolled arg parser (mod args) instead of clap
— breadpad doesn't use clap at all, and adding a second, separate clap
parser alongside the existing one would reject every one of breadpad's
real flags (--type, --no-classify, --status, fire, calendar, ...) the
moment it saw one clap didn't recognize. --screenshot/--output/--width/
--height are just three more fields on the same Args struct.

Only the "popup" view (the compose window) is wired up — the reminder
window needs a real stored Note to render, not worth fabricating one
just for a screenshot pass.

Also fixes the same single-instance footgun as the other apps: without
NON_UNIQUE, a screenshot run would just toggle-close the operator's real
already-open popup instead of getting its own window.

Cargo.lock

@@ -302,6 +302,16 @@ dependencies = [
  "piper",
 ]
 
+[[package]]
+name = "bread-screenshots"
+version = "0.3.1"
+source = "git+https://git.breadway.dev/Breadway/bread-ecosystem?branch=dev#1a3475bd2358202f60e29c9bd27d06b1428b1a27"
+dependencies = [
+ "anyhow",
+ "bread-utils",
+ "tracing",
+]
+
 [[package]]
 name = "bread-theme"
 version = "0.2.3"
@@ -313,6 +323,16 @@ dependencies = [
  "serde_json",
 ]
 
+[[package]]
+name = "bread-utils"
+version = "0.3.1"
+source = "git+https://git.breadway.dev/Breadway/bread-ecosystem?branch=dev#1a3475bd2358202f60e29c9bd27d06b1428b1a27"
+dependencies = [
+ "dirs 5.0.1",
+ "serde",
+ "serde_json",
+]
+
 [[package]]
 name = "breadman"
 version = "0.3.4"
@@ -335,6 +355,7 @@ name = "breadpad"
 version = "0.3.4"
 dependencies = [
  "anyhow",
+ "bread-screenshots",
  "breadpad-shared",
  "chrono",
  "dirs 5.0.1",